To Sip or Not to Sip? How Soups, Teas, and Water Shape Your Meal's Impact on Blood Sugar and Satiety

2025년 9월 28일

The age-old debate over pairing meals with liquids (tea, water, soup) goes beyond preference, tied to food physics, gastric function, and metabolism. Despite common wisdom, scientific clarity on how such pairings affect gastric emptying, blood glucose, and satiety has been lacking. This article synthesizes three authoritative nutritional studies covering Eastern and Western diets: rice with green tea, macaroni and cheese with water, and varied soup textures. Findings show rice-tea pairings (especially "chazuke-style") speed gastric emptying and boost postprandial blood glucose; frequent food-water sipping switches increase calorie intake by delaying sensory satiety; smooth pureed soups enhance fullness via slower gastric emptying but trigger higher blood glucose due to easier carbohydrate digestion. These insights disprove one-size-fits-all dietary myths, stressing optimal pairings depend on individual health goals (e.g., blood sugar/weight management) and calling for more research across diverse populations and meals.

Picture this: It’s a busy weeknight, and you’re settling into a favorite meal—maybe a bowl of fluffy white rice alongside a steaming cup of green tea, or a heaping plate of creamy macaroni and cheese with a glass of ice water. As you alternate between forkfuls and sips, a quiet question might cross your mind: Is this way of eating helping or hurting my body? For Americans navigating a landscape of conflicting dietary advice—from "drink water with meals to lose weight" to "avoid soup with carbs if you’re pre-diabetic"—these split-second choices feel loaded with unspoken consequences. Yet until recently, most guidance on meal-and-liquid pairings has been based on anecdote rather than hard science. How exactly do different liquids alter how quickly our stomachs empty? Does sipping while eating really affect blood sugar? And could that innocent glass of water be making us eat more than we need? To answer these everyday dining mysteries, we’re turning to three rigorous nutritional studies that unpack the science behind what happens when food and liquids meet in our bodies.

Does Rice with Tea Send Blood Sugar Skyrocketing?

White rice is a staple in many global diets, and tea remains a beloved dining companion—whether for cutting through richness or simply enhancing the meal experience. Yet opinions diverge sharply on their pairing: some swear by tea’s ability to aid digestion, while others worry it irritates the stomach or disrupts carbohydrate absorption. While prior research has explored digestive differences between solids and liquids, no studies had specifically examined how rice and tea pairings affect physiological responses—until now.

A 2025 study published in Physiology & Behavior set out to fill this gap, investigating how different rice-green tea combinations influence gastric emptying speed and postprandial blood glucose in healthy individuals. The goal was clear: to determine if "rice with tea" is a healthful habit or a dietary pitfall.

Study Participants

The research enrolled 12 healthy Japanese women aged 21–22 years, with BMIs ranging from 17.1 to 24.2 kg/m². All participants had no smoking history, food allergies, or metabolic disorders, and maintained fasting blood glucose levels of ≤6 mmol/L. The decision to focus on female participants was intended to minimize variability from gender differences, though it raises a key question for future research: Would these results translate to male populations?

Study Protocol

Employing a randomized crossover design, each participant consumed three different test meals over three days, with at least 3 days between meals to eliminate carryover effects from previous tests:

Rice-only group: 150 grams of white rice, cooked with water containing ¹³C-labeled sodium acetate to enable tracking of gastric emptying.
Rice + tea group: 150 grams of white rice paired with 200 milliliters of green tea.
Mixed group: 150 grams of white rice drizzled with 100 milliliters of green tea, plus an additional 100 milliliters of green tea on the side—mirroring the "chazuke" (tea-soaked rice) or "soup-soaked rice" common in some culinary traditions.

The green tea used was sugar-free and calorie-free, heated to 40°C before consumption. Participants were instructed to finish their rice within 4–7 minutes and drink the tea within 30–60 seconds—a pace that, while seemingly brisk, aligns with how many people eat in daily life. Over the subsequent 120 minutes, researchers monitored blood glucose levels using a glucometer and measured gastric emptying via the ¹³C-acetate breath test. Participants also used a Visual Analog Scale (VAS) to rate their feelings of hunger, fullness, and desire to eat post-meal.

Study Results

The data yielded surprising, myth-busting findings: First, both the "rice + tea group" and the "mixed group" exhibited significantly higher postprandial blood glucose levels compared to the rice-only group. The mixed group maintained higher glucose levels than the rice-only group between 10 and 60 minutes post-consumption, while the rice + tea group led from 20 to 45 minutes. When examining the incremental area under the curve (IAUC)—a measure of total glucose exposure— the mixed group’s IAUC0–60 (145.6 ± 51.6 mmol/l·min) was nearly 60% higher than that of the rice-only group (90.8 ± 44.1). The mixed group also reached a significantly higher peak glucose level (Cmax) of 8.11 ± 1.62 mmol/l, compared to 7.13 ± 1.45 mmol/l in the rice-only group.

Figure: Postprandial blood glucose changes across three eating methods. Both drinking tea after rice and consuming tea-soaked rice result in faster, more pronounced blood glucose spikes after meals.

Measurements of gastric emptying—specifically "half-emptying time (T1/2)" (the time needed to empty half the stomach contents) and "peak time (Tmax)" (when emptying speed is fastest)—showed that the rice-only group had the longest T1/2, while the mixed group had the shortest. This confirms that drinking tea accelerates the movement of rice from the stomach to the small intestine, where nutrients are absorbed. Further analysis revealed a positive correlation between gastric emptying speed and postprandial glucose levels: the faster the stomach empties, the quicker and more sharply blood glucose rises. This trend was most pronounced in the tea-soaked rice group, which saw the steepest glucose curve and highest peak levels in the first 60 minutes post-meal (as shown in the figure above).

Perhaps most unexpectedly, despite the stark differences in gastric emptying and glucose responses, there were no significant variations in participants’ subjective feelings of fullness, hunger, or eating desire across the three groups. In other words, eating rice while drinking tea or consuming tea-soaked rice causes the body to absorb glucose more rapidly and raises blood sugar higher—without making people feel any fuller. This finding contradicts the common intuition that "sipping liquids with meals boosts satiety," suggesting that adding liquids primarily alters digestive physiology rather than directly triggering the brain’s fullness signals.

So why does rice with tea cause blood sugar to "spike"? The researchers point to the stomach’s "sorting mechanism": Unlike bread, which absorbs liquid, rice remains physically separate from tea once in the stomach. The low-calorie, low-viscosity tea travels quickly through the stomach (acting like an "intragastric expressway"), carrying small portions of rice paste along with it. This accelerates carbohydrate absorption— and in turn, drives up blood glucose.

For individuals needing to manage blood sugar, these findings are clear: "chazuke," "soup-soaked rice," and similar liquid-rice combinations are best consumed sparingly.

Does Frequent Water-Sipping During Meals Make You Eat More?

"Drink more water to lose weight" is a ubiquitous piece of health advice—but does sipping water during meals actually help control portion sizes? A 2023 study published in Appetite focused on the behavioral pattern of switching between eating and drinking, exploring how this rhythm affects food intake across different meal sizes. The aim was to settle whether "frequent sipping while eating" helps reduce consumption or inadvertently leads to overeating.

Study Participants and Protocol

The study recruited 44 adults aged 18–68 years, with BMIs ranging from 19.0 to 33.7 kg/m². The cohort included 29 women and 15 men, with 46% classified as overweight or obese. All participants had no eating disorders, did not smoke, and expressed a liking for the test meal (macaroni and cheese)—a choice intended to eliminate bias from food aversions.

Over a 4-week period, participants took part in a randomized crossover experiment, visiting the lab once per week for a total of 4 lunch sessions. To assess the impact of portion size, each session offered a different quantity of macaroni and cheese: 400, 500, 600, or 700 grams. Each meal was paired with a consistent 700 grams of 4°C cold water, and the order of portion sizes was balanced using a Latin square design to avoid sequence effects.

Mealtimes were filmed in their entirety, and researchers used BORIS event-recording software to count bites, sips, and switching events (defined as taking a bite followed by a sip, or vice versa). To evaluate physiological and sensory changes, participants used a Visual Analog Scale (VAS) to rate hunger and fullness before and after eating, and completed a Specific Sensory Satiety (SSS) assessment—measuring how much their liking for macaroni and cheese decreased after eating.

Study Results

The findings are likely disappointing for proponents of "water-sipping for weight loss": The experiment showed that the more frequently participants switched between bites of food and sips of water, the more total food they consumed. For example, individuals who switched 10 times ate an average of nearly 30 grams more food than those who switched 5 times—equating to roughly 40 extra calories per meal. This suggests that water itself is not the primary driver of increased intake; instead, the rhythmic shift between eating and drinking provides constant new stimulation to the mouth, delaying sensory fatigue and leading to unplanned overconsumption.

Even more noteworthy: Despite eating significantly more, participants who switched frequently showed no meaningful difference in "specific sensory satiety"—the degree to which their preference for the food declined after eating—compared to those who ate less. A familiar real-world parallel illustrates this: Just as people often struggle to stop eating at buffets or while enjoying hot pot—alternating between meats, vegetables, and broths—frequent switching disrupts satiety signals, making it harder for the body to recognize when it’s full.

This behavioral insight complements the earlier rice-and-tea study: When rice and tea are consumed together, the liquid not only accelerates gastric emptying but the alternating eating-drinking pattern may also encourage greater food intake. These two factors work in tandem to drive higher postprandial blood glucose levels.

Figure: (A) The relationship between the number of switches between food bites and water sips, and (B) water intake volume, on food consumption among 44 adults.

What About Soup—Is It a Better Option?

"Eat soup before meals to control portions" is another widely shared dietary tip, but does the texture of soup—smooth and creamy versus chunky with pieces—actually influence how full it makes us feel? While many intuitively assume thicker, chunkier soups are more filling, this perception has long lacked scientific validation.

A 2013 study published in the European Journal of Clinical Nutrition sought to address this gap by examining the physiological mechanisms behind soup’s effects. It compared smooth soups, chunky thick soups, and regular solid meals across three key metrics: gastric emptying speed, postprandial glucose changes, and satiety—ultimately uncovering the science behind why "soup keeps you full."